48 



Eadweard Muyhridge 



[March 13, 



Fig. 6. Operating track, covered with corrugated indiariibber, and 

 marked with transverse lines 12 inches apart. Each line is numbered, 

 for the purpose of more readily ascertaining the length of the 

 animal's stride. On one side of the track, and opposite to the battery 

 of cameras, a white background is erected at a suitable angle. 



Fig. 6. 



The camera in which any one negative in a series of exposures is 

 made is designated on that negative by the parallel direction of the 

 vertical stake with the horizontal line extending to the corresponding 

 number immediately oj)posite. The discriminating number of each 

 series is marked on each negative by the large numbers — 229, for 

 example — which are changed for each movement illustrated. 



For recording the successive attitudes of animals not under 

 control, an apf)aratus is used, comprising a cylinder, around which 

 are spirally arranged a number of pins ; uj)on the cylinder being set 

 in motion through gearing connected with a spring or weight, these 

 pins are consecutively brought into contact with a corresponding 

 number of metal springs ; a succession of electric currents are thereby 

 created which act through their respective magnets attached to the 

 electro-exposors at regulated intervals of time. The cylinder is put in 

 motion either by bringing it into gearing with other parts of the appa- 

 ratus already in motion ; or by releasing a break with the hand, or by 

 the action of some object at a distance by means of an electric current. 



This apparatus is principally used for illustrating the flight of 

 birds, the motions of small animals, and changes of position without 

 continuous progressive motion, such as occur during wrestling or 

 turning a summersault ; when the cameras are directed towards the 

 place where the movements are being executed. 



The boxes outside the studio (Fig. 5) contain cameras and electro- 

 exposors for obtaining synchronous exj)osures of a moving object from 

 different points of view. 



The following analyses of some of the movements investigated by 



